[NFC][InstCombine] Fine-tune 'check for [no] signed truncation' tests
We are using i8 for these tests, and shifting by 4,
which is exactly the half of i8.
But as it is seen from the proofs https://rise4fun.com/Alive/mgu
KeptBits = bitwidth(%x) - MaskedBits,
so with using shifts by 4, we are not really testing that
we actually properly handle the other cases with shifts not by half...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337208 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed